The main objective of this project is to characterize the immunological properties and molecular nature of inappropriate antigens found on reticulum cell sarcoma derived from SJL/J mice. The role of these antigens in tumorogenesis is also being investigated. The presence of alien H-2 antigens was determined by several immunological tests including cell-mediated cytotoxicity, complement-dependent cytotoxicity, immunofluorescence and by opsonization. The biochemical nature of these antigens was determined by 2D gel analysis.